.tab {
  width: 500px;
  height: 500px;
  margin: 50px auto;
  border: 1px solid #000;
}

.tab .nav {
  height: 50px;
  border-bottom: 1px solid #000;
}

.tab .nav-item {
  float: left;
  width: 33.33%;
  height: 100%;
  text-align: center;
  line-height: 50px;
}

.tab .nav-item.current {
  background-color: #000;
  color: #fff;
}

.tab .page {
  position: relative;
  height: 450px;
}

.tab .page-item {
  display: none;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  text-align: center;
  line-height: 450px;
  font-size: 100px;
}

.tab .page-item.current {
  display: block;
}













